Gravity science is a major component of the JUNO Mission,
one of two selected by NASA for detailed study as a
candidate for the next mission in the New Frontiers Program.
The plan for JUNO is to insert a spinning spacecraft into an
eccentric orbit with period of about 11 days and a periapse
only a few thousand kilometers above Jupiter's surface. On
each of a possible 32 orbits, the Jovian gravitational field
is accessible for an observing interval of plus and minus
six hours from closest approach. On each observing run,
multi-link radio Doppler data are generated by the Deep
Space Network (DSN) in the X-Band (~8.4 GHz) and
Ka-Band (~34.3 GHz). This produces Doppler velocity
measurements to an accuracy of about 0.005 mm/s at a sample
interval of 60 s. We propose a gravity inversion technique
that can yield an accuracy of 10-9 for lower degree
normalized zonal harmonics through degree six, providing
information on Jupiter's core, and higher degree harmonics,
especially degree 12 through 30, can be measured to an
accuracy of about 10-8. The requirement on the gravity
measurements for a discrimination between solid-body
rotation and rotation in deep zonal flows has been discussed
by Hubbard (Icarus137 357). The proposed
inversion technique meets this requirement. In addition,
over the total time interval of 32 orbits, or about one
year, the polar precession rate can possibly be measured,
and tides raised by the five Jovian satellites JI to JV, as
reflected in the gravity data, can yield information on
Jupiter's Love numbers kn at five different depths in the
atmosphere.

The JPL contribution to this paper was performed at the Jet
Propulsion Laboratory, California Institute of Technology,
under contract with NASA. G.S. and J.L.P acknowledge support
by grants from NASA through the Planetary Geology and
Geophysics program.